7. A firm has a profit margin of 15 percent on sales of $20,000,000. If the firm has debt of $7,500,000, total assets of $22,500,000, and an after-tax interest cost on total debt of 5 percent, what is the firms ROA? a. 9.2 % b. 10.9 % c. 12.0 % d. 13.3 % e. 15.1 %